[Linux-stm32] [PATCH 07/22] ARM: dts: stm32: Add alternate pinmux for SDMMC2 pins 4-7

[Marek Vasut]

On 3/31/20 6:39 PM, Alexandre Torgue wrote:

Hi,

[...]

>>> I agree, and I prefer to keep pins groups definition in
>>> stm32mp15-pinctrl.dtsi file. IMO, it is easier for users to find them in
>>> only one file. Actually, I already had this discussions with some guys
>>> "where pins groups have to be defined ?". For me (and maybe only for
>>> me), muxing is SOC dependent, I mean SoC provides a bunch a possible
>>> pinmux for each IPs. If we got enough memory spaces (and time to waste
>>> also) we could define all possible pinmux (AFx....) for each devices and
>>> let board users chose the good one (using stm32mp15-pictrl.dtsi as a
>>> database). In board file, you select one possible pin configuration
>>> (provided by the SoC) for your device according to your schematic.
>>> However you could append pin groups in board file to update bias,
>>> slewrate ...
>>> If your concern it to embed a bunch of not used pin configuration for a
>>> board, we could use /omit-if-no-ref/ tag on pin groups.
>>
>> Can we instead define pinmux the way e.g. iMX6 does , as separate pins ,
>> instead of pinmux groups ?
>>
> 
> Sorry but what would the advantage to do so ?

You'd have per-board pinmux which would be perfect fit for that board,
without potentially affecting other boards with changes, without hacking
various things like drive-strengths in board files, and without having
the combinatorial explosion of the current single pinmux file.

-- 
Best regards,
Marek Vasut